In the past, a drum washing machine rotates a horizontal shaft drum in an outer tank storing water at a bottom thereof, thus washings are lifted up and dropped down by baffles arranged in the drum, and the washings are thrown to an inner circumferential surface of the drum to be washed (with reference to patent literature 1).
In this way, in a structure of stirring the washings by the baffles, the washings are difficult to twine or rub against each other. Therefore, compared with an automatic washing machine in which the washings are washed through rotation of a pulsator in a washing and spin-drying tank, the drum washing machine has a small mechanical force acted on the washings, and the detergency is reduced.
Therefore, the drum washing machine may adopt the following structure: a rotating body, the surface of which is provided with a projection, is arranged at a rear surface of the drum, and the drum and the rotating body can rotate at different rotating speeds during washing and rinsing. The washing performance can be improved by rubbing and stirring the washings through the rotating body.